Method and device for rearing insects, especially for obtaining secretion from fly larvae for therapeutic application

ABSTRACT

The invention relates to a device for breeding of insects for therapeutic application of secretions of fly larvae (maggots) on a wound. The device includes an application container for receiving the fly eggs. The fly larvae from the egg stage up to the maggot stage is develop inside the application container and the maggots are grown until they secrete a therapeutically active secretion. The application container is maintain under development conditions influenced in a controlled manner which retard the further development of the eggs for storage. The application container includes fluid transmissive walls that allow the passing of secretions produced by the maggot through the walls of the application container into the wound but prevents passage of the maggots enclosed in the application container. In addition, the device of the present invention includes an incubation container to maintain the eggs in controlled incubating conditions. The conditions for retarding the further development of the eggs includes at least one of cooling, dehumidification, evacuation, an inert gas atmosphere, and chemical or biochemical retardants, individually or in combination.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is Divisional of Ser. No. 09/762,575 FILED Feb.8, 2001, entitled “METHOD AND DEVICE FOR REARING INSECTS, ESPECIALLY FOROBTAINING SECRETION FROM FLY LARVAE FOR THERAPEUTIC APPLICATION”,allowed Dec. 13, 2002, which is a national stage of PCT/EP00/05132 filedJun. 6, 2002 and based upon DE 199 25 996.8 filed Jun. 8, 1999 under theInternational Convention.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] Process and device for rearing of insects, in particular forobtaining the secretions of fly larvae for therapeutic application.

[0004] 2. Description of the Related Art

[0005] The invention concerns a process and a device for rearinginsects, in particular for obtaining the secretions of fly larvae(maggots) for therapeutic application.

[0006] For treatment of wound infections and wounds, which containnecrotized tissue, for example for treatment of diabetic gangrene, flylarvae, so-called maggots, are employed, in particular larvae of Dipterafrom the family Muscidae, Sarcophaginae and Calliphoridae (for example,Lucilia, Blue Bottle). The larvae are introduced for a certain amount oftime, for example, approximately three days, into a wound for which itis difficult to render therapy. It has been shown that the larvae withinthis time removed necrotized tissue in the wound, eliminated bacterialinfections, and stimulated wound healing. This effect is in particularbrought about by the digestive secretions excreted by the maggots. Thissecretion fluidizes the necrotized tissue, so that it can be ingested bythe maggots as nutrition. The secretion further has a stronglybactericidal effect and promotes wound healing.

[0007] In this method of treatment it is necessary to have livingmaggots available which can be applied to the wound so that they secretethe healing secretions. This brings about, for the employment of thismethod, a substantial logistical problem, since the period of time ofthe active maggot stage, in which the healing secretions are secreted,is relatively short and has a duration of only a few days. It isnecessary that the maggots be transported from the producer, who breedsthe maggots, to the user immediately prior to application. Thisnecessitates an exactly coordinated plan. Besides this, the maggots arerelatively sensitive and must be provided with air and nutrients duringtransport. On the basis of these difficulties, the employment of the flylarvae therapy is limited in its possibilities and full advantage cannotbe taken thereof.

SUMMARY OF THE INVENTION

[0008] The invention is based on the task of providing a process and adevice through which the breeding of insects can occur in a controlledmanner, and in particular, through which the therapeutic application offly larvae secretion is simplified and facilitated.

DETAILED DESCRIPTION OF THE INVENTION

[0009] The essential idea of the invention is comprised therein, thatthe breeding of the insects is to be carried out in an enclosed biotopeunder exactly defined environmental conditions, as a result of which thedevelopment cycle can be intentionally influenced. Thereby it is madepossible to study the development and the behavior of the insects undertargeted, varied physical, chemical, biochemical, and biologicalconditions and to influence the conditions for the medical-therapeuticand pharmaceutical use. Thereby, the speed of the development cycle canbe influenced by changing the conditions, that is, it can be delayed oraccelerated. Besides this, it becomes possible by targeted, influencedmeasures to raise the quality and the yield.

[0010] In the utilization of the process for obtaining the secretion offly larvae for therapeutic application, one essential aspect iscomprised in arresting the development of the fly larvae in the eggstage and to store and/or to transport these eggs under developmentretarding conditions. At the manufacturer, who breeds the flies, the flyeggs are separated and preferably disinfected so that they aresufficiently sterile. The sterilized eggs are enclosed in aself-enclosed biotope, for example a container, in which the furtherdevelopment of the eggs is carried out or maintained under restrictiveor retarding conditions. Such conditions could include that the eggs arecooled and/or stored in a dehumidified atmosphere. Further, the eggs canbe stored in an oxygen-poor atmosphere, in which the container is, forexample, evacuated or filled with an inert gas. Further possible arereversible chemical/biochemical influences (for example Neb-TMOF), whichresults in oostasis for a defined period of time. These measures can beemployed individually or in combination. These resilient and toleranteggs can be kept alive for prolonged periods of time under theserestrictive development conditions. This makes it possible for theproducer to store the eggs for a certain period of time. Further, theeggs can be transported to the user in simple manner under theseconditions, without risk of damage. It is further possible for the enduser to maintain a certain supply of eggs, for example in a clinic, fora certain period of time, so that the respective actual needs can besatisfied.

[0011] If the maggot secretion is to be applied, then the userreactivates the further development of the eggs into the larval stage.For this, the development retarding conditions are lifted and the eggsare subjected to incubating conditions, so that they further develop andwithin a short period of time hatch into maggots. Since the eggs aresterilized at the producer, the hatched maggots are also sterile and canbe employed without problem.

[0012] It is also possible to culture microorganisms in the artificiallyproduced microbiologically-closed living environment, in order toheighten or to change the effect of the maggots and theirmicrobiologically modified secretions.

[0013] The maggots can be introduced immediately into the wound in theknown manner, and after a certain treatment time must again be removedfrom the wound. In one variation, the maggots are introduced in thewound in an application container. One such application containerincludes a fluid transmissive wall, which however does not allow passageof the maggots enclosed in the application container. For example, theapplication container can be a flexible bag with a net-like wall. Thesecretion secreted by the maggots can pass through the wall of theapplication container and into the wound. The wound tissue fluidized bythe secretion can likewise pass through the wall of the applicationcontainer and be taken up by the maggots. An application container ofthis type has the advantage, that the maggots and therewith thesecretions secreted by these maggots can be applied in targeted,localized manner. Besides this, maggots can be removed from the wound insimple manner, together with the application container.

[0014] Finally, it is also possible to bring the maggots into contactwith a porous wound insert, which absorbs the secretions secreted by themaggots. In this case, the wound insert soaked with the secretion isapplied to the wound. This has the advantage, that the wound insert canbe applied temporally and spatially separate from the maggots, whichsimplifies the application and avoids the problem of the occasionalpatient refusing treatment with living maggots.

[0015] Preferably the incubation of the eggs up to the hatching of themaggots occurs in an incubation container. The eggs are introduced inthis incubation container and incubated at a temperature of between 20and 40° C. The incubation container is provided with sufficient nutrientsubstances and air for the hatching larvae, so that these can develop upto the larval stage, at which they secrete the therapeutic secretions.This incubation container is preferably produced as a bag comprised ofplastic foil and preferably includes an absorbent material for absorbingthe produced active substances under sterile or microbiologicallycontrolled conditions.

[0016] In a preferred embodiment, the eggs can be enclosed in anapplication container and introduced into the incubation container.These small eggs are kept in the application container by the incubationcontainer, so that they do not fall out of this net-like wall. When thelarvae hatch out of the eggs, they can take up the nutrient substancesfrom out of the incubation container and grow in the applicationcontainer to the size at which they secrete the therapeutically activesecretions. At this size, they can no longer slip out of the net-likewall of the application container. The application container can then beremoved from the incubation container, or as the case may be, theincubation container can be moved from the application container, sothat the maggots can be applied to the wound directly with theapplication container, or can be brought into contact with a porouswound insert.

[0017] In an embodiment particularly simple for the user, the eggs areintroduced into the incubation container already by the producer andinitially maintained at development retarding conditions for storage andtransport. For this, the incubation containers are evacuated, or filledwith a dried inert gas, or are chemically/biochemically oostaticallymanipulated. Likewise, or in certain cases additionally, the incubationcontainers can be placed in a cooling container and cooled for storageand transport.

[0018] When the maggots are to be applied, incubation conditions areestablished in the incubation containers. For this, the incubationcontainers, together with the eggs, are introduced into a warmenvironment. The incubation containers are supplied withoxygen-containing air, the nutrients necessary for the hatching larvae,and in certain cases, activating chemical or biochemical factors (forexample peptidases). For administration of oxygen, the wall of theincubation container can be punctured with a canula, or an opening canbe provided. As appropriate, it is also possible to introduce thenecessary nutrients and, in certain cases, to introduce the oostaticinfluencing deactivating substances into the incubation container inthis manner. In a variation particularly convenient for the user, it ispossible that air, nutrient solutions, and other substances are providedin the incubation container during the manufacture thereof in enclosedcontainers or enclosed ampullae's, which can be disrupted by the user,so that air and nutrient solutions, as well as in certain caseschemical, biochemical, and microbiological components, are released intothe incubation containers, which promotes hatching and which can betaken up by the hatched maggots.

[0019] If the flies are transported to the user in the egg stage, sothat the maggots are hatched by the user for the application of thesecretion, then as a rule, the maggots are terminated as soon as theyare removed from the wound, or after they have secreted the secretiononto the wound insert.

[0020] At the producer, preferably utilizing a component of thepopulation of the insects, the complete development cycle is carried outin a time-wise modifiable and controllable biotope. After the hatchingof the maggots, these are in certain cases used for obtaining thesecretion, which then is made available for the user in the a formsuitable for application, or for manufacture of pharmaceuticalpreparations. At the end of the larvae stage, the conditions necessaryfor pupating are then established in the biotope, for example drying airconditions.

[0021] The maggots then pupate so that a new generation of insectshatches, which can then again be used for depositing of eggs understerile conditions. The raising of the insects from egg up to hatchedfly under time-wise, manipulable and controllable conditions providesthe producer with the possibility to match the time and yield of theproduction of the maggots, or as the case may be, the maggot secretions,to the market requirements. Besides this, the insect populations can bebred and influenced, in order to achieve an increase in productivity andquality. Finally, a targeted microbiological influence on the closeddevelopment biotope is possible, so that a therapeutic synergisticeffect can be achieved, for example by the select supplementation ofbacteria to the secretions secreted by the maggots.

What is claimed is:
 1. Process for breeding of insects, in particularfor obtaining the secretions of fly larvae (maggots) for the therapeuticapplication, wherein the development of the insects at least from eggstage up to maggot stage occurs in a closed biotope, in which thedevelopment-determining conditions are influenced in controlled manner.2. Process according to claim 1, wherein the time period of the eggstage is controlled for storage and/or transport by establishment,maintenance, and removal of development retarding conditions in thebiotope.
 3. Process according to claim 1 or 2, wherein the eggs aretransported to the user under development-retarding conditions, andwherein for preparing for application at the user-end the developmentretarding conditions are eliminated and incubation conditions areestablished, so that the maggots hatch and develop to the stage at whichthey secrete secretions for application.
 4. Process according to one ofclaims 1-3, wherein at the producer the entire development cycle fromthe egg deposit to the larvae, their further growth and pupating up tohatching of the adult insects, and renewed egg laying occurs in theenclosed biotope, and wherein the secretion secreted during the maggotstage is optionally collected for application.
 5. Process according toone of the preceding claims, wherein sterilized eggs are enclosed in thebiotope.
 6. Process according to claim 2, wherein the conditions forretarding the further development of the eggs includes cooling and/ordehumidification and/or evacuation and/or an inert gas atmosphere and/orchemical or biochemical retardants, individually or in combination. 7.Process according to one of the preceding claims, wherein the enclosedbiotope is established and maintained in a container.
 8. Processaccording to one of the preceding claims, wherein the eggs are subjectedto incubating conditions in an incubation container.
 9. Processaccording to one of the preceding claims, wherein the eggs areintroduced into an application container, which is trasmissive for thesecretions but through which the hatched maggots can however not passwhile they are subjected to the incubation conditions.
 10. Processaccording to claim 8 or 9, wherein the application container is enclosedin the incubation container.
 11. Process according to one of claims1-10, wherein the secretion from the maggots is applied directly to thewound.
 12. Process according to one of claims 1-10, wherein thesecretion secreted by the maggots is absorbed by a porous wound insert,which is then applied to the wound.
 13. Device for obtaining thesecretion of fly larvae (maggots) for therapeutic application, includinga container for receiving the fly eggs under conditions which retard thefurther development of the eggs.
 14. Device according to claim 13,characterized by an incubation container, in which incubation conditionsfor the eggs can be produced or maintained.
 15. Device according toclaim 13 or 14, characterized by an application container, in which theeggs can be introduced and in which the eggs can be maintained underincubation conditions, wherein the wall of the application container istransmissive for fluids, but however not transmissive for the hatchedmaggots.
 16. Device according to claim 15, thereby characterized, thatthe application container includes a flexible net-like wall.
 17. Deviceaccording to claim 14 or 15, thereby characterized, that the applicationcontainer is enclosed in the incubation container.
 18. Device accordingto one of claims 14-17, thereby characterized, that the incubationcontainer is a plastic foil container.
 19. Device according to one ofclaims 13-18, thereby characterized, that one or more incubationcontainers are provided in a container in which development retardingconditions are maintained.
 20. Device according to one of claims 13-18,thereby characterized, that in the incubation container first thedevelopment retarding conditions can be established and maintained and,as needed, can be converted to incubation and nurturing conditions. 21.Device according to one of claims 13-20, thereby characterized, that airand/or nutrients and/or chemical/biochemical/microbiological componentscan be supplied through the wall of the incubation container, inparticular using a canula.
 22. Device according to one of claims 13-20,thereby characterized, that air and/or nutrients and/orchemical/biochemical/microbiological components are provided in theincubation container enclosed in supply containers rupturable from theoutside, or can be supplied to it.